The present invention relates to a slide inclination correcting method and a slide inclination correcting apparatus in press machinery for correcting an inclination of a slide caused by an eccentric load that acts thereon in a press machine while the press machine is in the process of forming, especially a large work piece or a plurality of work pieces.
Many an existing press machine has a construction in which a slide is movable vertically up and down by a slide drive mechanism disposed in an upper area of the machine. The slide is used to carry on its lower surface a die (upper die) while another die (lower die) is mounted on a bed or bolster in the machine for forming a work piece between these dies.
Also, in a press machine that is relatively large in size and further in what is commonly called a transfer press, one such slide may often be used to form a plurality of work pieces simultaneously. In such cases, it has been experienced that different forming loads applied on the work pieces create an eccentric load acting on the slide.
The slide in a press machine is typically moved vertically up and down as guided on a slide gib laid on a slide body. An eccentric load if produced acting on the slide may cause the slide to be inclined. A deviation in position that will then result between the upper die attached to the slide and the lower die mounted on the bolster makes it impossible to perform forming with precision and also let the dies wear off quickly, thus reducing their life to a large extent.
Also, an inclination of the slide produces a localized rise in bearing pressure between the slide gib and the slide guided thereon, which disadvantageously causes these bearing surfaces to wear off soon or even the bearing members to seize up so that the press machine may become no longer operable.
In an attempt to obviate such disadvantages, there has been proposed an apparatus in the art that is designed to correct a slide inclination in a press machine, e.g., as disclosed in JP U S62-34998. This bulletin discloses a slide inclination correcting apparatus in a press machine, having a makeup in which a overload protector designed to protect the slide from an overload has a fluid chamber therein fed with pressure fluid if a slide inclination is detected.
The correcting apparatus disclosed in that bulletin which in correcting a slide inclination relies on feeding a pressure fluid into the overload protector upon detecting the slide inclination is found to leave itself to be desired, however, presenting several problems. Thus, a time consumed for a pressure to be raised in the overload protector until the inclined slide is properly leveled and a limited accuracy with which it is so raised cause the known apparatus to be of a relatively slow response and limited follow-up capability and hence to be poor in productivity and limited in the abilities to make an accurate correction and thus to form work pieces with precision.
With the view to circumventing the problems met in the prior art, it is an object of the present invention to provide a slide inclination correcting method and a slide inclination correcting apparatus in press machinery which method and apparatus make it possible to achieve forming with due precision without impairing the machine""s productivity. The present invention in one aspect thereof resides in finding by measurement or computation for each of dies or die sets an eccentric load that is to develop in the slide in the process of forming a work piece to prepare a die based slide inclination correcting data for each of the dies or die sets; and on the basis of the die based slide inclination correcting data prepared, pre-imparting to the slide a compensatory amount of inclination which corresponds to a predicted amount of inclination caused the slide due to the eccentric load found.
Thus, in order to achieve the object mentioned above, there is provided in accordance with the present invention in a first form of implementation thereof a slide inclination correcting method in press machinery having a slide drive mechanism disposed in a top area of a press machine for driving a slide via a plurality of points to vertically move it up and down, thereby forming a work piece, characterized in that the method comprises the steps of finding by measurement or computation for each of dies or die sets an eccentric load that is to develop in the slide in the process of forming a work piece to prepare a die based slide inclination correcting data for each of the dies or die sets; and on the basis of the die based slide inclination correcting data prepared, pre-imparting to the slide a compensatory amount of inclination which corresponds to a predicted amount of inclination caused the slide due to the eccentric load found.
According to the method described above, an eccentric load that does develop in the course of forming a work piece to act on a slide does not causes the slide to be inclined owing to the fact that a compensatory amount of inclination formed on the basis of a die based slide inclination correcting data for each of dies or die sets is pre-imparted to the slide to counteract the eccentric load. The effects of the method include the ability to form work pieces with due precision without impairing their productivity. Also, causing no deviation in position between an upper and a lower die, the method ensures preventing them from soon wearing off and does practically increases the die life.
The method described may specifically include the steps of detecting an actual amount of inclination of the slide on the basis of which a compensatory amount of inclination may be applied to the slide with the slide leveled thereby so that the slide and the upper surface of a bed or bolster become parallel to each other.
This specific method that seeks to maintain parallelism between the lower surface of the slide and the upper surface of the bed or bolster permits forming with due precision while impairing in no way the productivity. Also, causing no deviation in position between the upper and lower dies, the method ensures preventing them from soon wearing off and does practically increases the die life.
The method described may specifically include the steps of detecting an actual amount of inclination of the slide in the process of forming a work piece, using the actual amount of inclination detected to form a compensatory amount of slide inclination which corresponds thereto; and correcting the die based slide inclination correcting data by feeding back to the die based slide inclination correcting data the compensatory amount of inclination formed.
This specific method that allows the die based slide inclination correcting data to be enhanced in accuracy each time forming is repeated permits the compensatory amount of slide inclination that counteracts the eccentric load to be pre-imparted in each subsequent forming process to the slide in accordance with the die based slide inclination correcting data with a progressively increasing accuracy.
In order to achieve the object mentioned above, the present invention also provides in a second form of implementation thereof a slide inclination correcting apparatus in press machinery having a slide drive mechanism disposed in a top area of a press machine for driving a slide via a plurality of points to vertically move it up and down, thereby forming a work piece, characterized in that the apparatus comprises: a die based slide inclination correcting data acquisition means for acquiring a die based slide inclination correcting data by finding by measurement or computation for each of dies or die sets an eccentric load that is to develop in the slide in the process of forming a work piece; a fluid chamber provided for each of said points; and a slide inclination correcting means for adjusting quantity a fluid in the fluid chamber on the basis of the die based slide inclination correcting data acquired by the die based slide inclination correcting data acquisition means and thereby pre-imparting to the slide a compensatory amount of inclination that corresponds to a predicted amount of inclination caused the slide due to the eccentric load found.
According to the apparatus described above, an eccentric load that does develop in the course of forming a work piece to act on a slide does not causes the slide to be inclined owing to the fact that a compensatory amount of inclination formed on the basis of a die based slide inclination correcting data for each of dies or die sets is pre-imparted to the slide to counteract the eccentric load. The effects of the method include the ability to form work pieces with due precision without impairing their productivity. Also, causing no deviation in position between an upper and a lower die, the method ensures preventing them from soon wearing off and does practically increases the die life.
Specifically in the apparatus described, a said slide inclination correcting means may comprise a cylinder having a fluid chamber lying in communication with said fluid chamber, and the said compensatory amount of inclination is pre-imparted to the slide by opening and closing a valve means disposed between the first mentioned fluid chamber and the fluid chamber of the cylinder so as to set the fluid in the first mentioned fluid chamber free or let it escape into the fluid chamber in the cylinder.
The construction described above permits making a fine adjustment easily for the slide inclination and, also much being quicker in response and much better in follow-up capability than the prior art of supplying pressure fluid into a fluid chamber, allows the slide leveling to be accomplished promptly and with precision.
The apparatus so constructed as described above may further include a slide inclination detecting means for detecting an actual amount of inclination of the slide in the process of forming a work piece; and a means for applying to a said slide inclination correcting means a feedback control on the basis of a data derived from such detection by the said detecting means.
This specific construction that allows the die based slide inclination correcting data to be enhanced in accuracy each time forming is repeated permits the compensatory amount of slide inclination that counteracts the eccentric load to be pre-imparted in each subsequent forming operation to the slide in accordance with the die based slide inclination correcting data with a progressively increasing accuracy.
The apparatus so constructed as described above may further include a means for correcting the said die based slide inclination correcting data with the slide inclination data derived from detection by the slide inclination detecting means.
This specific construction which permits a die based slide inclination correcting data to be renewed on each occasion with an actual data for slide inclination allows increasing reliability of the die based slide inclination correcting data.
In order to achieve the object mentioned before, the present invention also provides in a third form of implementation thereof a method in which in pre-imparting a compensatory amount of inclination to the slide to compensate for the actual amount of its inclination due to the eccentric load as called for in the first form of implementation, adopts the step of supplying fluid into and discharging fluid from, a fluid chamber provided for each of the said points for the slide on the basis of the said die based slide inclination correcting data.
According to this method described above, an eccentric load that does develop in the course of forming a work piece to act on a slide does not causes the slide to be inclined owing to the fact that a compensatory amount of inclination formed on the basis of a die based slide inclination correcting data for each of dies or die sets is pre-imparted to the slide to counteract the eccentric load. The effects of the method include the ability to form work pieces with due precision without impairing their productivity. Also, causing no deviation in position between an upper and a lower die, the method ensures preventing them from soon wearing off and does practically increases the die life.
The method described above may further comprise the steps of: detecting by a slide inclination detecting means an actual amount of inclination of the slide in the process of forming a work piece; and applying to fluid pressure in the fluid chamber a feedback control on the basis of the actual amount of inclination detected, such that a lower surface of the slide and an upper surface of a bed or bolster becomes parallel to each other.
This specific method that seeks to maintain parallelism between the slide and the upper surface of the bed or bolster permits forming with due precision while impairing the productivity. Also, causing no deviation in position between the upper and lower dies, the method ensures preventing them from soon wearing off and does practically increases the die life.
The method described above may further comprise the steps of: detecting by a slide inclination detecting means an actual amount of inclination of the slide in the process of forming a work piece; and correcting the die based slide inclination correcting data by feeding back to the die based slide inclination correcting data a compensatory amount of slide inclination derived from the actual amount of inclination detected.
This specific construction which permits the die based slide inclination correcting data to be enhanced in accuracy each time forming is repeated allows the compensatory amount of slide inclination that counteracts the eccentric load to be pre-imparted in each subsequent forming operation to the slide in accordance with the die based slide inclination correcting data with a progressively increasing accuracy.
In order to achieve the object mentioned before, the present invention also provides in a fourth form of implementation thereof an apparatus construction wherein in the construction of the second form of implementation, the compensatory amount of inclination corresponding to the actual amount of inclination due to the eccentric load is pre-imparted to the slide by a said slide inclination correcting means when it acts to supply fluid into, and discharge fluid from, said each fluid chamber on the basis of a die based slide inclination correcting data as acquired by the said die based slide inclination correcting data acquisition means.
According to the construction described above, an eccentric load that does develop in the course of forming a work piece to act on a slide does not causes the slide to be inclined owing to the fact that a compensatory amount of inclination formed on the basis of a die based slide inclination correcting data for each of dies or die sets is pre-imparted to the slide to counteract the eccentric load. The effects of the method include the ability to form work pieces with due precision without impairing their productivity. Also, causing no deviation in position between an upper and a lower die, the method ensures preventing them from quickly wearing off and does practically increases the die life.
The apparatus described above may comprise a slide inclination detecting, means for detecting an actual amount of inclination of the slide in the process of forming a work piece; and a means for applying to fluid pressure in the fluid chamber a feedback control on the basis of the actual amount of inclination detected, such that a lower surface of the slide and an upper surface of a bed or bolster become parallel to each other.
This specific construction that seeks to maintain parallelism between the lower surface of the slide and the upper surface of the bed or bolster permits forming with due precision while impairing the productivity. Also, causing no deviation in position between the upper and lower dies, the method ensures preventing them from quickly wearing off and does practically increases the die life.
In the construction described above, the fluid chamber provided for each of the points preferably constitutes a fluid chamber for an overload protector.
The construction described above which permits utilizing a fluid chamber in the existing overload protector for each of the points in performing the correction of a slide inclination allows the apparatus of the invention to be manufactured economically, and, impairing in no way the existing overload protector, ensures that the slide drive mechanism is protected from a overload.
The apparatus described above may comprise a or the slide inclination detecting means for detecting the actual amount of inclination of the slide in the process of forming a work piece; and a means for correcting the die based slide inclination correcting data by feeding back to the die based slide inclination correcting data a compensatory amount of slide inclination derived from the actual amount of inclination detected.
This specific construction which permits the accuracy of the die based slide inclination correcting data to be enhanced each time forming is repeated allows the compensatory amount of slide inclination that counteracts the eccentric load to be pre-imparted in each subsequent forming operation to the slide in accordance with the die based slide inclination correcting data with a progressively increasing accuracy.
In order to achieve the object mentioned before, the present invention also provides in a fifth form of implementation thereof a slide inclination correcting apparatus in press machinery having a slide drive mechanism disposed in a top area of a press body for driving a slide via a plurality of points to vertically move it up and down, thereby forming a work piece, characterized in that the apparatus comprises: a die based slide inclination correcting data acquisition means for acquiring a die based slide inclination correcting data by finding by measurement or computation for each of dies or die sets an eccentric load that is to develop in the slide in the process of forming a work piece; a slide adjustment mechanism provided for each of said points; and a slide inclination correction means for pre-imparting to the slide a compensatory amount of inclination corresponding to a predicted amount of inclination caused the slide due to the eccentric load found, by driving said each slide adjustment mechanism on the basis of the die based slide inclination correcting data acquired by the said die based slide inclination correcting data acquisition means.
According to the construction described above, an eccentric load that does develop in the course of forming a work piece to act on a slide does not causes the slide to be inclined owing to the fact that a compensatory amount of inclination formed on the basis of a die based slide inclination correcting data for each of dies or die sets is pre-imparted to the slide to counteract the eccentric load. The effects of the method include the ability to form work pieces with due precision without impairing their productivity. Also, causing no deviation in position between an upper and a lower die, the method ensures preventing them from quickly wearing off and does practically increases the die life.
Also, designed to make the compensatory amount adjustable mechanically through a slide adjustment mechanism, this construction renders the compensatory amount less affected by heat, and thus allows the slide to be kept leveled with precision. In addition, being superior in reproducibility as well to hydraulics, it serves to yield products formed with an increased precision.
In the apparatus described above, an adjustment motor may be provided for the said slide adjustment mechanism provided for each of said each point.
This construction which permits the slide to be leveled by driving the slide adjustment mechanism for each of the points allows the slide in leveling to be adjusted horizontally in both longitudinal and transverse directions.
The apparatus described above may comprises sets of the said slide adjustment mechanisms with each set comprising a single or a plurality of slide adjustment mechanisms provided, respectively, with an adjustment motor.
This construction that permits simply providing an adjustment motor serves to reduce the number and the cost of parts and components. Reducing the number of adjustment motors also simplifies the entire control system.
The apparatus described above may further comprise a means for bringing an operation of a press machine when running to a halt if a relative difference between compensatory amounts of inclination of different slide adjustment mechanisms exceeds a pre-established value.
This construction allows the operating press machine to come to a halt when the slide is inclined beyond a pre-established value of inclination for a reason such as an error of entry and provides a preventive measure against a problem such as an unusual rise in bearing pressure between the slide and the slide gib which gives rise to an abnormal wear of the bearing surfaces and eventually a seizure there, rendering the slide no longer movable up or down.
The apparatus described above may further include a slide inclination detecting means for detecting an actual amount of inclination of the slide; and a means for applying to the slide adjustment mechanism a feed back control on the basis of the actual amount of inclination detected, such that a lower surface of the slide and an upper surface of a bed or bolster become parallel to each other.
This specific construction that seeks to maintain parallelism between the lower surface of the slide and the upper surface of the bed or bolster permits forming with due precision while impairing the productivity. Also, causing no deviation in position between the upper and lower dies, the method ensures preventing them from quickly wearing off and does practically increases the die life.
The apparatus described above may include a slide inclination detecting means for detecting an actual amount of inclination of the slide; and a means for feeding to the die based slide inclination correcting data a compensatory amount of inclination derived from the actual amount of inclination detected.
This specific construction which permits the accuracy of the die based slide inclination correcting data to be enhanced each time forming is repeated allows the compensatory amount of slide inclination that counteracts the eccentric load to be pre-imparted in each subsequent forming operation to the slide in accordance with the die based slide inclination correcting data with a progressively increasing accuracy.
These and other features, objects and advantages of the invention will be more readily understood or apparent to those skilled in the art from a reading of the following detailed description of preferred forms of embodiment of the present invention as illustrated in the various drawing figures.